The proposed work uses a novel technique to (1) investigate the basic biology of healing in balloon-angioplasty injury of arterial wall and (2) point the direction to new interventional therapies which will inhibit intimal hyperplasia and restenosis. In the first part of the project, blockade of platelet deposition will be used to investigate mechanisms of intimal thickening. The permeability of both thrombus-preventing and thrombus- inducing barriers will be varied to systematically investigate the role of circulating and thrombus-generated factors in a clean fashion. In the next part of the work, the protein release characteristics of the blockading gels will be investigated and the gels will be used to locally perturb healing by release of thrombin and PDGF, which are known to influence the healing process. Finally, endothelial-cell adhesion- promoting peptides will be incorporporated into degradable gels to develop a material which will enhance re-endothelialization of the injury site.